Process of bleaching by electrolytic chlorin water.



No. 655,239. Patented Aug. 7, I900.

' T.JESPERSEN.

PROCESS OF'BLEACHINGBY ELECTROLYTIC CHLOBIN WATER.

(Application filed May 29, 1899.) (No Model.)

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NITED rares rATENT" THOMAS JESPERSEN, on .NEENAH, WISCONSIN.

PROCESS OF HBLEACHING: BY ELECTROLYTIC CHLORIN WATER.

SPECIFICATION forming partof Letters Patent No. 655,239, dated August 7,1900.

Application filed May 29,1899. Serial No. 718,679. (No specimens.)

To allwhom it may concern:

Be it known that I, THOMAS J EsrEnsEN, a citizen of the UnitedStates,'an'd a'resident of Neenah, in the county of Winnebago and Stateof Wisconsin, have invented certain new and useful Improvements inProcesses of Bleaching by Electrolytic Ghlorin Water, of which thefollowing is a specification.

In bleaching vegetable fiber-"such as paper-pulp, cotton, or linengoods-by my process electricity is used to decompose a dilute waterysolution of hydrochloric acid in such a Way that the chlorin gas evolvedat the immersed anode is absorbed by the water of the surrounding waterysolution of the electrolyte, forming thereby chlorin 'water. Phus thewatery solution serves as an electrolyte and as a carrier of chlorinsimultaneously. The material to be bleached is also held suspended inthis solution and may be agitated in a convenient manner to facilitatethe uniform saturation of the contents of the tank in which the materialto be bleached is held. The bleaching now proceeds in the usual mannerby the decomposition of the water by the absorbed chlorin, yieldingnascent oxygen and hydrochloricacid. Thus chlorin, while combining withthe hydrogen of the water, is constantly. reproducing an electrolyte,(hydrochloric acid,) which can again be subjected to the action of theelectric "current, yielding at the anode chlorin, which, asbefore, willbe absorbed by the water, decomposing it to form oxygen and hydrochloricacid, as before, and at the cathode hydrogen, which is allowed toescape. Thus the chlorin may be used over and over in the same mannerindefinitely, thereby cheapening the process of bleaching by savingmaterial.

In using hydrochloricacid as an electrolyte in bleaching fibroussubstances there are two distinct features for which I claim originalityand superior usefulness over other processes heretofore usedi first, thedirect formation chloric acid may be added one or more soluble chlorids,which, however, will not change the chemical reaction nor the ultimateresult.

In order to carry out my process, it is essential that a suitable tankis provided for holding the necessary solution, the material to bebleached, and the electrolyzing apparatus.

If the material to be bleached is paperstock, the usual washer orbeater-engine tank is preferable, (the washer and beater-engine beingsubstantially the same in construction,) the revolutions of thebeater-knifecyli'nder serving to agitate the paper-stock-whilebeingacted upon by the electrolyzed solution beater-engine tank may beused,.and the various operations of agitating the solution and materialto be bleached or of removing the liquid from the tank can be performedby manual labor or by any suitable means which is available.

In the drawings, Figure 1 shows a plan of a beater-engine tank andrepresents the manner in which I propose to apply my process forbleaching paper-stock. Fig. 2 is a vertical sectionof the tank on theline a, a of Fig. 1. Similar numerals indicate like parts in both views.

l indicates the washer or beater-engine tank; 2, the shaft which carriesthe beaterknives; 3, the journal-boxes in which the shaft revolves; at,the beater-knife cylindercover; 5, its driving-pulleys; 6, a partitiondividing the tank into sections along its-line of greatest length for apart of its -central portion; 7, the pulp-washer; 8, the washer-shaft;9, journal-boxes supporting said shaft; 10, a pulley by which the washermay be revolved by means of the belt 11 from the pulley 12 upon the endof the shaft 2; 13, a spout leading from the washer for discharging thewater which the washer dips up in its revolutions outside of the tank;14, astorage-tank for holding said water until it is required to bereturned to the tank for bleaching another charge of paper-stock; 15, apump for the return of the Water to the tank; 16, a pipe connecting thepump and storage-tank; 17, a pipe from the pump to the beater-enginetank; 18, a recess in the bottom of the tank for holding the anode; 19,the anode; 20, a binding-screw connecting with the anode and by means ofthe wire21 connecting the anode witha Supply of electricity; 22, aperforated screen which separates the'pulpto be'bleached from directcontact with the anode. screen may be of wood or metal perforated,

- or it may be of wire-cloth, which is preferable,

as it will permit the free contact of the liquid without allowing thepulpy material of the paper-stock to come in contact with the This levelof the solution, dipping into it slightly, as in Fig. 2, to make contactin such a way as to alloweasy escape of the hydrogen liberated by theelectrical current. The material to be bleached is placed in the tankwith a solution of the electrolyte, which consists of dilutehydrochloric acid In the electrolysis of hydrochloric'acid chlorin gasis evolved at the anode. This gas is readily absorbed by the surroundingwater, forming chlorin water, which in the act of bleaching willreproduce hydrochloric acid. This hydrochloric acid -remaining-insolution is again subjected to electrolysis, with the same result asbefore. Thus the process is rendered continuous. At the cathode hydrogengas is evolved, which will rise to the surface of the solution. It isnot desirable to have this free hydrogen pass through the body of theelectrolyte charged with free chlorin on account of the affinity"existing between the gases, which in combinstock in its passageover-the anode 'to be saturated with chlorin.

In the drawings, 1 represents a container serving both as a bleachingand electrolyzin g tank. The anode 19 is recessed into the bottom of thetank and screened by means of a perforated screen of some suitablematerial in order to allow the chlorin gas to be absorbed mosteffectually by the superincuma bent stratum of watery solution of theelectrolyte mixed with the material to be bleached without allowing saidmaterial to come in' contact with the anode. This screen may be made ofbrass wire-cloth, but other forms-of a suitable material may be used, orother material which will not be aflected injuriously by the chemicalsused. A carbon anode at which chlorin is liberated in the nascent statewill be slowly corroded by that gas, causing minute particles of carbonto be dislodged constantly from that anode. These minute 7 particles ofcarbon, if not in some wayprevented from mixing with the material to bebleached, will impart a blackish discoloration to the materiahthusdefeatingthe object of the process. Friction between the anode and thematerial will materially increase the amount of carbon dislodged. Toovercome this objecing would lessen the amount of available freechlorin. To overcome this objection, the cathode may be placed as nearthe surface of the solution as possible, thus reducing the objection toaminimum.

After the bleaching operation has been completed the bleachedmaterial isto be separated from the solution, whichsolu tion is nowready to receivea new charge of materiahto be bleached; This separation maybe made inany convenient manner. In the present case it is being done by means ofthe washer 7, which'is continually delivering the liquid con-' tents ofthe tank 1 to the storage-tank 14, from whence it can be returned to thetank 1 by means ofthe pump 15 for the succeeding charge, of paper-stock.

7 Having described my invention, what I claim, and desireto secure byLetters Patent,

1. The process of bleaching, consisting of electrolyzing a dilute waterysolution of hydrochloric acid, allowing the chlorin gas liberated at theimmersed anode to dissolve in the water of said watery solution.bleachin with the resulting chlorin water, and by the act of bleachingrestoring hydrochloric acid to the solution and again electrolyzingasbefore, all of the processes being performed simultaneously andcontinuously in the same tank or container, substantially as'described.

2. The process of bleaching, consisting of electrolyzing an aqueoussolutioncontainlng hydrochloric acid, allowing the chlorin gas liberatedat the immersed anode to dissolve in the said aqueous solution,bleaching with the resulting chlorin water, and by the act of bleachingrestoring hydrochloric acid to the solution and again electrolyzing asbefore, all of the processes being performed simultaneously andcontinuously in the same tank tion,"I have arranged the anode in theabovestated manner.

The cathode is placed at a point or line corresponding with thesurfaceorcontainer, substantially as described. 7

3. The process of bleaching, consisting of electrolyzing an aqueoussolution of oneor inore chlorids containing hydrochloric acid, allowingthe chlorin gas liberated at the immersed anode to dissolve in saidaqueous solution, bleaching with the resulting chlorin water, and by theact of bleaching restoring hydrochloric acid to the solution and againelectrolyzing as before, all of the processes being performedsimultaneously and eontinu ously in the same tank or retainer,substantially as described.

THOMAS J ESPERSEN. Witnesses:

S. B. MORGAN, W. G. BROWN.

